Probing permeation of energetic hydrogen atoms through molybdenum disulphide on graphene platform

Graphene and h-BN are known to be permeating for thermal protons, molybdenum disulphide (MoS₂) is found to block them. We report permeation of highly energetic hydrogen atoms produced from electron beam irradiation of hydrogen silsesquioxane resist through MoS₂ layers on graphene platform. Single-layer graphene has been used as a detector to estimate permeation. Extent of hydrogenation of graphene, estimated from Raman spectroscopy studies, was used to quantify the permeation of hydrogen atoms through monolayer, tri-layer and bulk MoS₂. A decrease in defect density induced in graphene was observed with increasing layer numbers of MoS₂. This data was used to estimate the absorption coefficient of MoS₂ using the defect density n _D , with a value close to 0.06 Å⁻¹. The percentage transmission of hydrogen atoms was found to be 65% per layer. (paper)